Displaying 20 results from an estimated 700 matches similar to: "getting the normal dist from the chisqr with 1df"
2007 May 07
2
computing logrank statistic/test
hie how do you compute the logrank test using R
what commands do you use my data looks something like just an example
treatmentgrp strata censoringTime survivalTime censoring act.surv.time
[1,] 2 2 42.89005 1847.3358 1 42.89005
[2,] 1 1 74.40379 440.3467 1 74.40379
[3,] 2 2
2007 May 07
4
creating a new column
hie l would like to create a 6th column "actual surv time" from the following data
the condition being
if censoringTime>survivaltime then actual survtime =survival time
else actual survtime =censoring time
the code l used to create the data is
s=2
while(s!=0){ n=20
m<-matrix(nrow=n,ncol=4)
2007 May 17
2
controling the size of vectors in a matrix
hie R users
l have the following matrix
n=20
m<-matrix(nrow=n,ncol=4)
colnames(m)=c("treatmentgrp","strata","survivalTime")
for(i in 1:n) m[i,]<-c(sample(c(1,2),1,replace=TRUE),sample(c(1:2),1,replace=TRUE),rexp(1,0.07),rexp(1,0.02))
2007 May 01
1
adding column to a matrix
l have the following dataset and would like to calculate the actual survival time by
if censoring time > survival time then actual survival time =survival time else its= censoring time.
treatmentgrp strata censoringTime survivalTime censoring actualsurvivaltim
[1,] 1 1 1.012159 1137.80922 0
[2,] 2 2
2007 May 17
1
creating columns
l would like to create the following matrice
treatmentgrp strata
1 1 1 1 1 1 1 2 1 2 1 2 2 1 2 1 2 1 2 2 2 2 2 2 l should be able to choose the size of the treatment grps and stratas the method l used intially creates the
2007 May 03
0
unscrible pls
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2007 Apr 26
3
adding a column to a matrix
i would like to add a variable to an existing matrix by manipulating 2 previous variables eg for the data
m
treat strata censti survTime
[1,] 1 2 284.684074 690.4961005
[2,] 1 1 172.764515 32.3990335
[3,] 1 1 2393.195400 24.6145279
[4,] 2 1 30.364771 8.0272267
[5,] 1 1 523.182282 554.7659501
l
2007 May 01
7
logrank test
how do l programme the logrank test. l am trying to compare 2 survival curves
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2007 May 14
1
logrank
hie
is it possible to get the code for the logrank test l just need the chisquared value.
thanks
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2011 Nov 20
1
Cox proportional hazards confidence intervals
I am calculating cox propotional hazards models with the coxph
function from the survival package. My data relates to failure of
various types of endovascular interventions. I can successfully
obtain the LR, Wald, and Score test p-values from the coxph.object, as
well as the hazard ratio as follows:
formula.obj = Surv(days, status) ~ type
coxph.model = coxph(formula.obj, df)
fit =
2008 Feb 28
0
surv2sample 0.1-2
Dear useRs,
There is a new version 0.1-2 of the package surv2sample available on CRAN.
Users of the previous versions should update because a bug in the function
cif2.ks has been fixed.
General information about the package:
surv2sample provides various two-sample tests for right-censored survival
data. Three main areas and corresponding methods are:
* comparison of two survival
2008 Feb 28
0
surv2sample 0.1-2
Dear useRs,
There is a new version 0.1-2 of the package surv2sample available on CRAN.
Users of the previous versions should update because a bug in the function
cif2.ks has been fixed.
General information about the package:
surv2sample provides various two-sample tests for right-censored survival
data. Three main areas and corresponding methods are:
* comparison of two survival
2006 Jan 03
1
p-value of Logrank-Test
Hello!
I want to compare two Kaplan-Meier-Curves by using the Logrank-Test:
logrank(Surv(time[b], status[b]) ~ group[b])
This way I only get the value of the test-statistic, but not the p-value.
Does anybody know how I can get the p-value?
Thanks in advance!
Verena Hoffmann
2012 Jun 19
1
weird --no 'dimnames' attribute for array-- error for R lordif package
Hi All,
? I am trying to use the lordif package in R and can't figure out the reason for the above error when I try to run the calctheta() function.
##################
# read data using foreign package - must be Stata 11 or earlier
racedata<- read.dta("race.dta")???
# item responses
resp.data<-racedata[,-c(1:2)]
# grouping variable is in the second column
2013 Apr 02
0
coxph and variables
Dear list,I am quite new to the world of biostatistics and I encounter some
issues in the precise understanding of the coxph function of the survival
package.I have a set of survival data (patient who had (or died from) a
breast cancer) I'd like to see which are the variables that might cause dead
or not.When trying> summary(coxph(Surv(Time_to_distant_recurrence_yrs,
!Distant_recurrence)~
2005 Jun 22
1
chisq test and fisher exact test
Hi,
I have a text mining project and currently I am working on feature
generation/selection part.
My plan is selecting a set of words or word combinations which have
better discriminant capability than other words in telling the group
id's (2 classes in this case) for a dataset which has 2,000,000
documents.
One approach is using "contrast-set association rule mining" while the
2009 Aug 03
0
new package: interval
I have just uploaded a new package called interval. It does weighted logrank tests (e.g., logrank, Wilcoxon-type tests) on interval censored data. It allows Surv objects and can calculated exact p-values. It calls the perm package, but also allows calculation of scores that may be output to faster permutation packages like coin.
There is a full description of the packge and methods in a
2009 Aug 03
0
new package: interval
I have just uploaded a new package called interval. It does weighted logrank tests (e.g., logrank, Wilcoxon-type tests) on interval censored data. It allows Surv objects and can calculated exact p-values. It calls the perm package, but also allows calculation of scores that may be output to faster permutation packages like coin.
There is a full description of the packge and methods in a
2010 Jul 17
0
Adjustment for multiple-comparison for log-rank test
DeaR experts,
I was asked for a log-rank pairwise survival comparison. I've a straightforward way
to do this using the SAS system:
http://support.sas.com/documentation/cdl/en/statug/63033/HTML/default/viewer.htm#/documentation/cdl/en/statug/63033/HTML/default/statug_lifetest_sect019.htm
What I've found in R is shown below, but it's not a logrank test,
I suppose. (The documentation
2010 Feb 04
0
Update of interval package
Hi all,
I have uploaded an update of the interval package, which calculates nonparametric maximum likelihood estimates (NPMLE) of distributions and exact or asymptotic weighted logrank-type tests for interval censored data. An important part of the update is that now the default initial estimate of the NPMLE uses the MLEcens package and is much faster. This increases the speed of the logrank-type